1. When the iPhone 4 was launched, its price was much lower, about RMB1000. 2. When you were calling someone, maybe your phone would be hung up.-- I don't understand what you want to say.
Sorry, maybe I don't make myself clear. Iphone 4 and iphone 4s are different. I don't think I should use "its" in the first sentence. In the second sentence, what I want to say is that there is some signal problem of the iphone 4s, so it may be hang up or cut off? Sorry, I don't know how to express it. Can you help me with this sentence?
Ah, sorry— I don't have a cellphone, so I didn't recognize the names; but it should be a capital 'S'. Let me rephrase #1:
1. When the iPhone 4Swas launched, the price of the iPhone 4 dropped to about RMB1000. 2. When you were calling someone, sometimes your call would be cut off.